In recent years, non-contact identification devices for transmitting radio signals become increasingly popular, and these devices generally come with a main body and an external read/write device for exchanging information to achieve the effects of information transmission and identification. Radio Frequency Identification (RFID) tag is a new radio transmission device used extensively in many areas such as logistics management, merchandise management, medical management, etc. Due to the non-contact characteristic and the simple application, RFID systems have gradually replace traditional contact identification systems such as barcode scanning identification systems.
The so-called RFID tag generally includes a RFID chip and an antenna coupled to the RFID chip. Radio signals are transmitted from the RFID chip to an external read/write device through the antenna for transmitting and receiving data to achieve the identification effect.
The RFID tag is mainly divided into an active RFID tag and a passive RFID tag. For the active RFID tag, electric power can be supplied from an external power supply (such as a battery or a cell) to the RFID tag; and for the passive RFID tag, electric power of radio waves of the external read/write device is supplied to the RFID tag directly.
Since the RFID tag is thin, its application is convenient. The passive RFID tag is used mostly, but the passive RFID tag can just be used for signal transmissions within a short distance for a short time. If the distance of a read/write device is far from the RFID tag, then the signal transmission will become very weak. Therefore, the passive RFID tag always has the issue of insufficient transmission distance. Although the active RFID tag can be used as a device to substitute the passive RFID tag for long-distance signal transmissions, most power supply devices of the traditional active RFID tag are battery manufactured by old manufacturing processes, and thus the active RFID tag not just comes with a large volume only, but also consumes much power. Therefore, it is necessary to develop a RFID device capable of overcoming the transmission distance, volume, and power-saving issues concurrently.